Operation of spark-ignition engines



Aug. 21, 1962 M. R. BARUSCH 3,050,043

OPERATION OF SPARK-IGNITION ENGINES Filed April 1,1960

CARBURETOR k ENGINE J I Am I BODY 7 4 12 1r H ff 0 0o 0 5 o o o o 00 00 o I 10 E k 6 :::'-':::t g x 3 ,4 I E CRANKCASE INVENTQR MAug/cE a '60 ATTORNEYS United States Patent ()fifice 3,050,043 Patented Aug. 21, 1952 3,050,043 OPERATION OF SPARK-IGNITION ENGINES Maurice R. Barusch, Richmond, Califl, assignor to California Research Qorporation, San Francisco, Calif., a corporation of Delaware Filed Apr. 1, 1960, Ser. No. 19,211 3 Claims. (Cl. 1231) This invention relates to an improved method of operating spark-ignition internal combustion engines. More particularly, it is concerned with an improved method of operating spark-ignition engines provided With special means for removing engine blowby gases from. the crankcase and directing them into the intake system whence they pass into the combustion chamber to be completely burned, thus effectively reducing atmospheric pollution.

In certain types of automotive engine service, rough idling and engine stalling has long been a problem and has required frequent carburetor adjustments and carburetor and engine reconditioning in order to maintain satisfactory operation. This problem of poor engine operation has been accentuated and expanded with the increased traffic density in metropolitan areas and the use of multiathroat carburetors in private automobiles. It has been determined that a primary factor in poor idling operation is an accumulation of deposits in the throttle body section of the carburetor, which causes an over-rich mixture at idle and a reduction in idle speed. The accumulation of deposits in the induction system of the engine, and particularly in the throttle section of the carburetor, is particularly pronounced in services requiring considerable idling, such as taxicab and door-todoor delivery service. In private automobile operation, this problem is particularly emphasized in the metro! politan areas, where heavy city traffic is encountered with appreciable stop-and-go driving.

The problem of deposits accumulated in the induction system of a spark-ignition engine is equally acute in stationary spark-ignition engines whenever they have to run a considerable time at idle, for instance, in the operation of generator sets in electric power plants and the like industrial installations.

Insofar as carburetor deposits are concerned, the critical accumulation point for these deposits is on the wall of the throttle body of the carburetor adjacent to the throttle plate, whose position controls the idle air-fuel ratio. As these deposits accumulate, the air flow at idle is restricted with no change in fuel flow and an over-rich mixture results, causing erratic idling and engine stalling. In order to compensate for the presence of these deposits, the throttle must be opened slightly by increasing the idle speed adjustment, which, although allowing more air flow, automatically supplies more fuel. This requires a fuel correction by changing the idle fuel adjustment screw a compensating amount. The amount of idle fuel adjustment required to maintain satisfactory idle performance is an indication of the deposit build-up. Furthermore, deposits will often form in the idle fuel, vacuum-breaking, air passageway, causing restriction, which allows the manifold vacuum to draw more gasoline into the engine, again causing n'ch idle and engine stalling.

It has been established that the primary source of these carburetor deposits is provided by the contaminants in the intake air of the engine when operating at idle. The greatest source of these intake air contaminants is engine blowby, which accounts for approximately ne half of the deposits. The term blowby refers to air-fuel mixture gases and burned gases which have been compressed and leaked past the piston rings from the combustion chamber into the crankcase. At idle, under the engine hood of an automobile, or within the housing of a stationary engine, a large portion of these blowby gases penetrates into the engines air intake. Exhaust from other vehicles, dust, and other air pollutants, further contribute to the formation of deposits.

The hydrocarbon components of the gasoline fuel bear no direct relation to the formation of these noted deposits except as the composition of blowby is affected. Tests have indicated that unstable or aged gasolines having high ASTM gum or high potential gum values produce no greater carburetor deposits than stable low-gum gasolines under comparable operating conditions.

In addition to the aforementioned deposits, further deposition occurs in the intake manifold and ports, and on the underside of the intake valve heads of sparkignition engines due to causes distinct from those previously discussed. One of the major sources of these supplementary deposits is the phenomenon known as puff back, which is the passage of combustion gases from the combustion chamber of the engine through the intake valves into the intake ports immediately prior to the intake stroke. This puff back carries combustion deposits which tend to lay down on the surfaces of the intake ports and valves. Additional deposits, particularly those formed in the intake manifold, are derived from existent gims present in the gasoline, the decomposition of the anti-knock lead alkyl additive, such as tetraethyl lead, small amounts of gums formed by oxidation of the gasoline in the intake manifold, exhaust gases, road dust, and the like.

The presence of the deposits in the intake manifold, ports, and on the underside of the intake valve heads leads to a reduction in power output of the engine as a result of throttling the intake fuel-air mixture. With the increasing trend on the part of engine manufacturers to improve volumetric efiiciency at high engine speeds, the deleterious effect of these deposits becomes a more serious problem. Additionally, the formation of deposits on the intake manifold surface, which acts as a heat exchanger to improve fuel vaporization, reduces heat transfer and considerably extends the warm-up period of the engine.

In the copending application Serial No. 784,467, filed January 2, 1959, and now abandoned, of which the present application is a continuation-in-part, there has been described and claimed an effective method of operating a spark-ignition internal combustion engine under conditions which ordinarily contribute to considerable depositformation in the air-fuel intake system of the engine, namely, under conditions which involve drawing into the intake system the blowby gases and the air surrounding the engine contaminated by dust and other air pollutants. A substantial portion of these pollutants, in the case of an automobile in the heavy, stop-and-go city trafiic, is contributed by blowby and exhaust gases from other motor vehicles.

The aforementioned application, instead of recommending resort to periodic mechanical adjustments and engine reconditioning for the purpose of compensating for the presence and accumulation of carburetor and induction system deposits, proposed to prevent the build-up of these deposits and to decrease the existing deposits by operating the engine on an improved, specially compounded fuel composition. According to the aforementioned applica tion, by operating the engine on a leaded hydrocarbon base fuel, boiling essentially in the gasoline boiling range from about to about 450 F. and compounded with a small amount of an oil-soluble acyclic alkylene diamine, the build-up of the deposits in the carburetor and in the induction system due to the admission thereto of the blowby, etc., will be effectively inhibited and in all events substantially reduced.

The term leaded hydrocarbon base fuel boiling essentially in the gasoline boiling range or simply leaded gaso line, as it is employed in the present description, is intended to designate liquid hydrocarbon fuels boiling in the gasoline boiling range, suitable, accordingly, for use in spark-ignition internal combustion engines and containing lead alkyl additives, such as lead tetraethyl or the like lead alkyls in amounts comonly employed in commercial automotive fuels to prevent occurrence of the engine knock.

The particular class of alkylene diamine compounds which function as the above-mentioned unique improving agents may be represented by the following general formula:

wherein R is an acyclic hydrocarbon group containing from about 12 to carbon atoms and R is an alkylene group containing from 2 to 3 carbon atoms.

A particularly preferred diamine comprises one in which R is a propylene group and R is an acyclic hydrocarbon group derived from tallow acids. The term tallow acids refers to higher fatty acids present in tallow (beef, mutton, etc.) in the form of glycerides. Not less than about by weight of the acids in tallow are unsaturated C C fatty acids (mainly oleic). More generally, the unsaturated acid content is from to by weight. An oil-soluble acyclic alkylene diarnine material derived from such tallow is available under the registered trademark Duomeen T. Other desirable diamines comprise those in which R is an acyclic hydrocarbon group derived from fatty acids obtained from coconut oil or oleic acid (cis-9- octadecenoic acid). These latter compounds are available under the trademarks Duomeen C and Duomeen 0, respectively, and comprise mixed acyclic hydrocarbon substituted propylene diamines. For example, in the case of Duomeen T, the R group contains a mixture of tallowderived acyclic hydrocarbon groups having from about 12 to about 20 carbon atoms and predominantly containing groups having 16 to 18 carbon atoms. The R groups of Duomeen C are predominantly 12 carbon atom groups, and those of Duomeen O are largely composed of straight-chain 18-carbon atom olefinic groups.

The alkylene diamine improving agents by reason of their unique effectiveness, are incorporated in the hydrocarbon base fuel in relatively small amounts, and preferably within the range of from about 0.0002 to 0.20 percent by weight. A still more preferred range is one wherein the improving agents are incorporated in the fuel in amounts of from about 0.003 to 0.10 percent by weight. In addition to the subject improving agents in the fuel compositions, other conventional fuel additives may be incorporated therein, as, for example, anti-knock or knocksuppressing agents (tetraethyl lead, etc.), surface-ignition suppressants, such as phosphorus-containing compounds, dyes, gum and oxidation inhibitors, and the like, provided they are used in such amounts as not to interfere with the beneficial action of the diamine additives of the invention.

An added factor is the reduction of deposits within the air-fuel induction system of the engine can be obtained by the incorporation, in combination with the subject improving agents, of a relatively nonvolatile oil, such as a mineral lubricating oil or a petroleum spray oil, which functions as a carrier for the deposits dispersed by the diamine improving agents. Satisfactory results have been obtained by incorporating an oil in the concentration range of between 0.05 to 3.0 percent by volume. Such compositions have shown effectiveness in the reduction of deposits in the area of the intake ports of the engine.

It is usually desirable to formulate the aforementioned improving agents in the form of a concentrate to facilitate handling problems and to permit a simple blending operation in the incorporation of the additive in the fuel. In the preparation of the concentrate, the improving agent is dissolved in a solvent, preferably alcoholic or aromatic in nature and boiling within the gasoline boiling range, in a concentration of from about 10 to 70 percent by weight.

As pointed out hereinbefore, blowby is formed partly by the unburned hydrocarbon vapors of the fuel-air mixture and partly by the combustion gases leaking past piston rings from the combustion chamber into the crankcase. In view of the fact that the unburned hydrocarbon blowby gases escaping into the atmosphere tend to contribute to the occurrence of smog reaction, the industry has been striving to develop means and devices which would effectively convey (recirculate) the blowby gases from the crankcase to the combustion chamber in order to achieve their complete combustion. The general idea of effecting this transport of blowby contemplates a line or conduit leading from a suitable connection, such as a check valve, fitted onto the body of the crankcase, to a convenient point of the intake system, for instance, on the air cleaner above the carburetor, or on the throttle body just below the carburetor, or on the heat riser, or on one or several of the legs (branches) of the intake manifold, or in any other manner permitting to accomplish the desired purpose. Preferably, the piping which serves to evacuate the blowby from the crankcase, whether connected thereto directly, or through a check valve, or through an adaptor combined with the check valve, is joined in a suitable fashion to the air-fuel intake system just below the carburetor and the throttle plate, but above the manifold. Another arrangement would be to tap a hole on one, or on several, or on all of the legs or branches of the manifold and to connect the piping to the intake system at that point (or those points).

Irrespective of the particular system or devices for conveying the blowby gases from the crankcase to the intake system of a spark-ignition engine, employment of leaded gasoline compounded with a small but effective amount of an oil-soluble acyclic alkylene diamine, as fuel for the operation of the engine, prevents formation and accumulation of deposits which would otherwise result from the introduction of the blowby in the intake system and/or in various portions thereof, such as intake ports, manifolds, intake-valve underheads, etc. In the attached drawing, FIGURE 1 represents a schematic diagram of one of such systems for transport (piping) of blowby gases from the crankcase to the combustion chamber. This figure shows the body of an automobile engine with the corresponding locations of air breather 1, air cleaner 2, and dip stick tube 3. The travel of blowby, past piston 4 and piston rings 5 of one of the cylinders 6 to the crankcase, is indicated by arrows 7. Draft tube 8, in the instant illustration, is removed from the body of the crankcase as shown by dotted lines, and, in lieu thereof, adaptor 9 with check valve 10 is fitted onto the crankcase. Pipe 11 connects valve 10 with the intake system which comprises the carburetor, throttle body 12, heat riser 14, the manifold and its several branches 15. Arrows 13 indicate the path of the ventilation air arriving through breather 1 into the crankcase and thence, on becoming mixed together with the blowby, passing through valve 10 and piping 11 into the intake system at throttle body 12. The exact location of adaptor 9 and valve 10 on the crankcase is not critical, and it may be placed closer or farther away from the location of the draft tube in which case this tube will be plugged tight.

My improved method of operating a spark-ignition engine on the combination of leaded gasoline and alkylene diamine lends itself particularly well to the operation of engines equipped with like devices for piping the blowby gases back to the combustion chamber. Since in driving automobiles and trucks considerable vacuum is created in the intake manifold (as much as 10" to 12"), it will be readily realized that the provision of a simple pipe connection or line from the crankcase to the manifold is apt to create the problem of drawing into the intake system some oil vapors, and even some liquid oil together with the blowby gases. Therefore, in a number of systems, the piping for conveying the blowby from the crankcase to the air-fuel intake system may be provided with suitable devices, such as spring-operated check valves, to prevent an inordinate drawing-in of the oil into the manifoid, and, in addition, to prevent occurrence of a backfire due to a sudden flashing of the blowby gases.

The following examples are now presented to illustrate the utility, effectiveness and unique characteristics of fuels containing the improving agents of the invention.

A laboratory test to facilitate observation and evaluation of deposits was developed. In this test, a glass throttle body is inserted between the venturi section and the cast iron throttle body of a conventional carburetor. This glass throttle body is a section of glass tubing A-inch thick, approximately 1% inches inside diameter, and about 2 inches long. About A-inch down from the upper edge, holes are drilled diametrically to receive a conventional metal throttle shaft and plate. The carburetor and engine employed in the test are those of a 6-cylinder Plymouth automobile.

The engine is operated a total of two hours on the test gasoline at about 500 r.p.m. idle, with 5 full-throttle, no-load accelerations, up to a speed of about 3,000 rpm. every minutes during the test period. During each run, the engine blowby is piped to the engines air cleaner on top of the carburetor. At the end of the test run, the engine is shut down and the glass throttle body removed and rated in accordance with the degree of deposits on a scale ranging from 1 to 7. A rating of 1 indicates a complete lack of deposits with the throttle body clean, and a rating of 7 indicates substantially complete coverage with black, opaque deposits. This test procedure and the rating of compounded gasolines obtained thereby have found excellent correlation with actual test operations in the field.

EXAMPLE I In this particular example, the diamine additive is an aminopropyl tallow amine, i.e., Duomen T.

The following results were obtained.

Fuel composition: Deposit rating Base fuel 6.0 Base fuel plus 500 p.p.m. of diamine 3.5

EXAMPLE II In another test, several combinations of the same leaded gasoline base fuel and different diarnines were tested in comparison with the base fuel alone. In carrying out the foregoing test procedure, the following representative data were obtained.

Deposit rating Base fuel 6. Base fuel+10 p.p.m. Duomeen T (avg. of 4 runs) 5.2 Base fuel+20 p.p.m. Duomeen T (avg. of 4 runs) 4.4 Base fue1+30 p.p.m. Duomeen T (avg. of 4 runs) 2.2 Base fuel+100 p.p.m. Duomeen T (avg. of 4 runs) 1.8 Base fue1+30 p.p.m. Duomeen 0 (avg. of 4 runs) 3.1 Base fuel+30 p.p.m. Duomeen C (avg. of 5 runs) 4.8 Base fuel+30 p.p.m. N-hexadecyl ethylenediamine (avg.

of 4 runs) 3.1

EXAMPLE III In this example, the same leaded base fuel containing the same diamine additive as in Example I is employed to operate an engine provided with the blowby-piping device illustrated in FIGURE 1, other test conditions being substantially the same as in the test of Example I.

At the end of this test, it is again observed that the deposit formation is drastically minimized leaving the interior of the intake system, including the carburetor, intake ports, and inside Walls of the branches of the manifold, substantially free of deposits.

EXAMPLE IV As noted above, Examples 1, II and III emphasize the effectiveness of the special fuel composition for preventing the accumulation of deposits in the carburetor of a spark-ignition engine, these deposits being essentially independent of the fuel composition. The present example stresses the effectiveness of the fuel composition of the invention in removing and preventing deposits in the intake manifold and intake ports of the induction system, these deposits being due largely to puff back and the fuel composition itself, besides the blowby.

A gasoline composition, comprising a regular grade commercial gasoline base fuel containing tetraethyl lead, oxidation and rust inhibitors, was compounded with 500 parts per million of Duomeen T according to the invention. This fuel was employed in 10 taxicabs of a commercial fleet. For comparative purposes, 10 other taxicabs of the same fleet, and the same make automobile, operating under essentially identical conditions, were field tested employing the same base fuel but with no Duomeen T additive. In each case, prior to the test, the intake manifold volumes and the intake port volumes were determined. Since all of the automobiles tested had been previously operated, none were free of deposits and thus, the initial volumes were considerably less than Would be the case in new automobiles. For example, the approximate clean manifold volume of these 20 automobiles was 580 cc. each. At the start of the test, the manifold volume had been reduced, by deposit formation, to an average of about 490 cc., thereby indicating an average of about 90 cc. of deposits per automobile. In all cases, volumes were determined by water displacement and have an accuracy of about 1 percent. Additionally, the tests were conducted to determine the effect of the exhaust heat control valve under normal conditions (manifold is coldest when the control valve is open and hottest when closed) and in both completely closed and completely open positions, which would represent malfunctions commonly found in service. The results of these tests are shown in the following tables.

Table l REDUCTION OF INTAKE MANIFOLD DEPOSITS [Base fuel+500 p.p.m. Duomeen T." Approximate clean manifold volume, cc.580]

Manifold Manifold Initial Deposits Deposit;

Taxicab Heat Valve V01. V01. Miles on Deposits, Removed, Red11c- Position Before After Test cc. cc. tion, Vol.

Test, cc. Test, cc. Percent On 525 568 5, 776 43 86 Ofi 515 558 6, 737 43 66 Normal. 496 565 8, 417 84 69 82 do 497 560 10, 273 83 63 76 n 438 555 10, 381 142 117 82 Normal... 517 570 11,519 63 53 84 do 482 556 12, 063 98 74 76 Off 453 533 12, 415 127 63 Normal... 435 558 12, 527 145 123 do 485 560 14. 074 75 79 The 10 taxicabs employing the base fuel alone were inspected in the same manner, the test miles ranging from-7,086 to 12,914 miles with the average being 10,030 miles; It was found that the amount of deposits in the intake manifold remained essentiallyconstant. The fact that the amount of deposition did not increase to any great extent is attributed to the test being conducted in the winter employing a Winter grade base fuel having a lower equilibrium deposit level than the summer grade gasoline upon which the automobiles'had been operated on prior to these tests.

The results of the same tests on intake port deposits are as shown in the following Table II.

Table 11 REDUCTION OF INTAKE PORT DEPOSITS [Base fuel ppm. Duomeen T"] As in the case of the manifold deposits, very small changes occurred in the port deposits of the 10 vehicles employing the base fuel alone.

From the above two table it is clearly apparent that, in addition to the carburetor deposit removal shown by the results in Examples I, II and III, extremely large amounts of deposits formed in the intake manifold and ports can be removed. Thus, an average of 78 percent of the existing deposits in the intake manifolds of automobiles operated under the severest of conditions were removed after an average mileage of only slightly over ten thousand miles. Greater deposit removal would be expected from continued operation.

From the above result it can be seen that the operation of a spark-ignition engine on the fuel composition containing' the particular aforedescribed alkylene diamines, effectively prevents and reduces accumulation of all types of 'deposits'encountered in the carburetor and in the induction system of such an engine and, in particular, when such engine is equipped with means for piping the blowby from the crankcase -to the intake system.

I claim:

1. The method of operating a spark-ignition internal combustion engine equipped with means for recycling engine blowby gases into the air-fuel intake system so as to simultaneously reduce atmospheric air pollution from engine exhaust gases and to prevent accumulation of de posits in the air-fuel intake and carburetor system of said engine,.the steps which comprise passing the engine blowby gases, atmospheric air, and a leaded gasoline into said air-fuel intake system and carburetor and thence into the combustion chamber of the engine, burning said gasoline in said combustion chamber, the blowby gases being returned to the air-fuel intake system, said leaded gasoline containing a minor amount suificient to prevent accumulation of deposits as a result of said blowby gas circulation, Within the range of about 0.0002% to about 0.2% by weight of said gasoline of an oil-soluble acyclic alkylene diamine selected from the group consisting of cis-9-octadecenyl-1,3-propylene diamine, and aminopropyl tallow amine wherein the tallow radical is an acyclic hydrocarbon group of 16-18 carbon atoms.

2. The method according to claim 1 wherein the diamine is cis-9-ootadecenyl-1,3-propylene diamine.

3. The method according to claim 1 wherein the diamine is aminopropyl tallow amine wherein the tallow radical is an acyclic hydrocarbon group of 16-18 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS 1,483,186 Minge Feb. 12, 1924 1,517,326 Watkins Dec. 2, 1924 1,869,262 Kennedy July 26, 1932 2,139,801 Boyce Dec. 13, 1938 2,736,658 Pfohl et a1. Feb. 28, 1956 2,891,850 Cosgrove et al June 23, 1959 

1. THE METHOD OF OPERATING A SPARK-IGNITION INTERNAL COMBUSTION ENGINE EQUIPPED WITH MEANS FOR RECYCLING ENGEIN BLOWBY GASES INTO THE AIR-FUEL INTAKE SYSTEM SO AS TO SIMULTANEOUSLY RADUCE ATMOSPHORIC AIR POLLUTION FROM ENGINE EXHAUST GASES AND TO PREVENT ACCUMULATION OF DEPOSITS IN THE AIR-INTAKE AND CARBURETOR SYSTEM OF SAID ENGINE, THE STEPS WHICH COMPRISE PASSING THE ENGINE BLOWBY GASES, ATMOSPHERIC AIR, AND A LEADED GASOLINE INTO SAID AIR-FUEL INTAKE SYSTEM AND CARBURETOR AND THENCE INTO THE COMBUSTION CHAMBER OF THE ENGINE, BURNING SAID GASOLINE IN SAID COMBUSTION CHAMBER, THE BLOWBY GASES BEING RETURNED TO THE AIR-FUEL INTAKE SYSTEM, SAID LEADED GASOLINE CONTAINING A MINOR AMOUNT SUFFICIENT TO PREVENT ACCUMULATION DEPOSTIS AS A RESULT OF SAID BLOWBY GAS CIRCULATION, WITHIN THE RANGE OF ABOUT 0.0002% TO ABOUT 0.2% BY WEIGHT OF SAID GASOLINE OF AN OIL-SOLUBLE ACYCLIC ALKYLENE DIAMINE SELECTED FROM THE GROUP CONSISTING OF CIS-9-OCTADECENYL-1,3-PROPYLENE DIAMINE, AND AMINOPROPYL TALLOW AMINE WHEREIN THE TALLOW RADICAL IS AN ACYCLIC HYDROCARBON GROUP OF 19-18 CARBON ATOMS. 